ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13)—also known as von Willebrand factor-cleaving protease (VWFCP)—is a zinc-containing metalloprotease enzyme that cleaves von Willebrand factor (vWf), a large protein involved in blood clotting. It is secreted in blood and degrades large vWf multimers, decreasing their activity.Genomically, ADAMTS13 shares many properties with the 19 member ADAMTS family, all of which are characterised by a protease domain (the part that performs the protein hydrolysis), an adjacent disintegrin domain and one or more thrombospondin domains. ADAMTS13 in fact has eight thrombospondin domains. It has no hydrophobic transmembrane domain, and hence it not anchored in the cell membrane.